Imperial Japanese Navy

The Imperial Japanese Navy (IJN) was the navy of the Empire of Japan from the Meiji Restoration to 1945. It was built up from ships handed over by the shogunate and the domains; in 1872 the Ministry of Military Affairs was divided into Army and Navy Ministries, the latter at Tsukiji in Tokyo. The operational command became independent in 1893 as the Navy General Staff (renamed Gunreibu in 1933), standing alongside the administrative Navy Ministry. The coast was divided into naval districts each under a chinjufu: Yokosuka (1884), Kure and Sasebo (1889) and Maizuru (1901), each with an arsenal, barracks, hospital and defence units, creating four naval-port cities.

Victory in the Sino-Japanese and Russo-Japanese Wars, above all the Battle of Tsushima in 1905, established the Navy's international standing. The Washington (1922) and London (1930) naval treaties capped capital ships and auxiliaries and split the officer corps into "treaty" and "fleet" factions. After Japan left the treaty system, the treaty-free era from 1937 saw construction of the Yamato-class battleships alongside the development of land-based attack aircraft and carrier task forces.

By the start of the Pacific War, it was the third-largest navy in the world and operated the most advanced carrier fleet; Japanese sources give about 385 vessels (including 10 battleships) and more than 3,260 aircraft in December 1941. It was responsible for naval operations across the Pacific and Indian Oceans, from Pearl Harbor to Midway to the defense of the home islands. Midway in June 1942 cost four fleet carriers, and attrition in the Solomons consumed its trained aircrew. After the Battle of the Philippine Sea (June 1944) and Leyte Gulf (October 1944) the Combined Fleet lost the capacity for organised operations; the Navy formed the first Kamikaze special attack units in the Philippines that October, and the battleship Yamato was sunk en route to Okinawa in April 1945.

The Navy was dissolved after the surrender; the Navy Ministry was abolished on November 30, 1945 and became the Second Demobilization Ministry, responsible for demobilisation and minesweeping. The Japan Maritime Self-Defense Force, founded in 1954, uses the former naval ports of Yokosuka, Kure, Sasebo and Maizuru. Navy sites on this website include naval district and arsenal facilities, air group bases, communications and fuel installations, and training bases for special attack weapons.